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-rw-r--r--kernel/power/hibernate.c20
-rw-r--r--kernel/power/main.c55
-rw-r--r--kernel/power/suspend.c4
3 files changed, 72 insertions, 7 deletions
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index aa9e916da4d..f6120291663 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -277,7 +277,7 @@ static int create_image(int platform_mode)
goto Enable_irqs;
}
- if (hibernation_test(TEST_CORE))
+ if (hibernation_test(TEST_CORE) || !pm_check_wakeup_events())
goto Power_up;
in_suspend = 1;
@@ -288,8 +288,10 @@ static int create_image(int platform_mode)
error);
/* Restore control flow magically appears here */
restore_processor_state();
- if (!in_suspend)
+ if (!in_suspend) {
+ events_check_enabled = false;
platform_leave(platform_mode);
+ }
Power_up:
sysdev_resume();
@@ -511,14 +513,20 @@ int hibernation_platform_enter(void)
local_irq_disable();
sysdev_suspend(PMSG_HIBERNATE);
+ if (!pm_check_wakeup_events()) {
+ error = -EAGAIN;
+ goto Power_up;
+ }
+
hibernation_ops->enter();
/* We should never get here */
while (1);
- /*
- * We don't need to reenable the nonboot CPUs or resume consoles, since
- * the system is going to be halted anyway.
- */
+ Power_up:
+ sysdev_resume();
+ local_irq_enable();
+ enable_nonboot_cpus();
+
Platform_finish:
hibernation_ops->finish();
diff --git a/kernel/power/main.c b/kernel/power/main.c
index b58800b21fc..62b0bc6e498 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -204,6 +204,60 @@ static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
power_attr(state);
+#ifdef CONFIG_PM_SLEEP
+/*
+ * The 'wakeup_count' attribute, along with the functions defined in
+ * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
+ * handled in a non-racy way.
+ *
+ * If a wakeup event occurs when the system is in a sleep state, it simply is
+ * woken up. In turn, if an event that would wake the system up from a sleep
+ * state occurs when it is undergoing a transition to that sleep state, the
+ * transition should be aborted. Moreover, if such an event occurs when the
+ * system is in the working state, an attempt to start a transition to the
+ * given sleep state should fail during certain period after the detection of
+ * the event. Using the 'state' attribute alone is not sufficient to satisfy
+ * these requirements, because a wakeup event may occur exactly when 'state'
+ * is being written to and may be delivered to user space right before it is
+ * frozen, so the event will remain only partially processed until the system is
+ * woken up by another event. In particular, it won't cause the transition to
+ * a sleep state to be aborted.
+ *
+ * This difficulty may be overcome if user space uses 'wakeup_count' before
+ * writing to 'state'. It first should read from 'wakeup_count' and store
+ * the read value. Then, after carrying out its own preparations for the system
+ * transition to a sleep state, it should write the stored value to
+ * 'wakeup_count'. If that fails, at least one wakeup event has occured since
+ * 'wakeup_count' was read and 'state' should not be written to. Otherwise, it
+ * is allowed to write to 'state', but the transition will be aborted if there
+ * are any wakeup events detected after 'wakeup_count' was written to.
+ */
+
+static ssize_t wakeup_count_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ unsigned long val;
+
+ return pm_get_wakeup_count(&val) ? sprintf(buf, "%lu\n", val) : -EINTR;
+}
+
+static ssize_t wakeup_count_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *buf, size_t n)
+{
+ unsigned long val;
+
+ if (sscanf(buf, "%lu", &val) == 1) {
+ if (pm_save_wakeup_count(val))
+ return n;
+ }
+ return -EINVAL;
+}
+
+power_attr(wakeup_count);
+#endif /* CONFIG_PM_SLEEP */
+
#ifdef CONFIG_PM_TRACE
int pm_trace_enabled;
@@ -236,6 +290,7 @@ static struct attribute * g[] = {
#endif
#ifdef CONFIG_PM_SLEEP
&pm_async_attr.attr,
+ &wakeup_count_attr.attr,
#ifdef CONFIG_PM_DEBUG
&pm_test_attr.attr,
#endif
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index f37cb7dd440..5f8d09f9432 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -163,8 +163,10 @@ static int suspend_enter(suspend_state_t state)
error = sysdev_suspend(PMSG_SUSPEND);
if (!error) {
- if (!suspend_test(TEST_CORE))
+ if (!suspend_test(TEST_CORE) && pm_check_wakeup_events()) {
error = suspend_ops->enter(state);
+ events_check_enabled = false;
+ }
sysdev_resume();
}